Disposable defibrillator electrode assembly

ABSTRACT

A disposable electrode assembly for a portable defibrillator ( 12 ) comprises defibrillator electrodes ( 14 ), batteries ( 24 ) for powering the defibrillator, and a connector ( 22 ) for connecting the electrodes and batteries to the defibrillator. The connector has power output terminals ( 20 ) for connecting the battery to the defibrillator and high voltage input terminals ( 20 ) for applying a defibrillation voltage to the electrodes. The batteries ( 24 ) are housed in the connector ( 22 ) or mounted on the rear of one electrode

This invention relates to a disposable electrode assembly for a portabledefibrillator.

Portable defibrillators have been available for the last 20 years. Theoperation of these devices has always involved, at minimum, threeactions: step (1) applying a power source to the device (either througha battery pack or a mains plug); step (2) plugging a set ofdefibrillation electrodes (pads) into the device and applying theelectrodes to the patient's bare chest, and step (3) turning the deviceon (either via an on/off button or opening a lid, etc.).

In a public situation, e.g. a railway station, airport or the like, itis desirable that the device be operable by a lay member of the publicwithout undue complication.

Accordingly, it is an object of the invention to simplify the operationof a portable defibrillator, at least to the extent that steps (1) and(2) above are combined.

According to an aspect of the present invention, there is provided adisposable electrode assembly as specified in claim 1.

The invention further provides a combination of a defibrillator and adisposable electrode assembly as specified in claim 7.

It is a subsidiary object of the invention also to eliminate step (3)above, so that a single action will power the defibrillator and turn iton.

A subsidiary benefit of the invention is that in conventionaldefibrillation using disposable pads and batteries, battery managementmust be carefully considered and constantly monitored. The presentinvention separates the process of battery management from thedefibrillation process by incorporating the power source for thedefibrillator within the disposable electrode assembly.

The invention is also directed to a method by which the describedapparatus operates and including method steps for carrying out everyfunction of the apparatus.

The invention will be understood in greater detail from the followingdescription of preferred embodiments thereof given by way of exampleonly and with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram of a first embodiment of the invention;

FIG. 2 shows a modification of the embodiment of FIG. 1;

FIGS. 3 to 9 are schematic diagrams of further embodiments of theinvention;

FIG. 10 is an exploded perspective view of a practical implementation ofthe embodiment of FIG. 7;

FIG. 11 is a top perspective view of a further embodiment of theinvention;

FIG. 12 is a top perspective view of the combined pad and batteryhousing of the embodiment of FIG. 11, omitting the pads;

FIG. 13 is a top perspective view of the combined pad and batteryhousing of the embodiment of FIG. 11, including the pads;

FIG. 14 is a perspective view of the underside of the combined pad andbattery housing of the embodiment of FIG. 11;

FIG. 15 is a top perspective view of the defibrillator to which thecombined pad and battery housing is fitted;

FIG. 16 shows the pads used in the embodiment of FIG. 11;

FIG. 17 is a cross-sectional view of the combined pad and batteryhousing of the embodiment of FIG. 11, including the pads;

FIG. 18 is a top perspective view, similar to FIG. 13, of a combined padand battery housing of a still further embodiment of the invention;

FIG. 19 is a cross-sectional view of the combined pad and batteryhousing of FIG. 18.

In the drawings, the same or equivalent components have the samereference numerals.

Referring to FIG. 1, a first embodiment of disposable electrode assembly10 for a portable defibrillator 12 comprises a pair of defibrillationelectrodes (hereafter referred to simply as “pads”) 14 hermeticallysealed in a pouch 16 from which they may be removed for use by removinga “tear-off” strip 17. Flexible electrically conductive leads 18 connectthe pads 14 to respective ones of a pair of outer terminals 20 of aconnector 22. The connector 22 also houses a set of batteries 24 whichare connected in series across a pair of inner terminals 26 of theconnector 22.

In use the connector 22 is plugged into a complementary connector 28 ofthe defibrillator 12. The complementary connector 28 has a pair of outerterminals 30 which are engaged by the terminals 20 of the connector 22,and a pair of inner terminals 32 which are engaged by the terminals 26of the connector 22. Thus, the terminals 26 of the connector 22 arepower output terminals which in use supply power to the defibrillator 12via the terminals 32, while the terminals 20 of the connector 22 arehigh voltage input terminals which receive from the defibrillator 12,via the terminals 30, a defibrillation voltage for application to thepads 14.

The defibrillator 12 may be turned on automatically by insertion of theconnector 22 into the connector 28, or it may be turned on by somefurther action as will be described. In any event, save for the locationof the batteries in the connector 22, in all other respects thedefibrillator may be entirely conventional.

FIG. 2 shows a modification to FIG. 1, where the pouch 16 contains avoice module 34 comprising a speaker 36, a speaker IC 37, and its ownpower cell 38. This is activated upon removing the tear-off strip 17 togive spoken instructions to the lay user how to plug in the connector 22from which point the defibrillator itself shall take over the operation.Voice modules 34 are well known and used, for example, in the noveltygreetings card industry.

In another embodiment, FIG. 3, the power supply circuit which connectsthe batteries 24 in series within the connector 22 includes a springbiased contact 39. This is biased towards a counter contact (not shown)but is maintained out of engagement with such counter contact by aninsulating tab 40 interposed between the two. Removal of the tear-offstrip 17 to open the pouch 16 pulls the tab 40 from under the contact39, allowing it to engage its counter contact and thus automaticallycomplete the power supply circuit within the connector 22.

A variation of this includes means for sensing when the pads 14 areseparated, FIG. 4, by low power monitoring circuitry internal to thedefibrillator 12 which checks to see if an electrical connection 41between the pads 14 has been broken. The defibrillator 12 turns itselfon when the connection 41 is sensed as broken, meaning that the pads 14have been removed from the pouch 16 and separated. One way of doing thisis shown in the circuit diagram of FIG. 4A.

The pads 14, here individually referenced 14A and 14B to distinguish onefrom the other, are mounted on a release liner 15 within the pouch 16(not shown). The connection 41, having a resistance R3, is also mountedon the liner 15 and creates an electrical link between the two pads 14Aand 14B. As described, the pads 14A and 14B are attached to theconnector 22 containing the batteries 24 which supply a voltageV_(batt).

When the connector 22 is plugged into the defibrillator 12 the pads 14Aand 14B are connected to a changeover unit 80 (such as a relay) havingchangeover contacts 82. Initially, as seen in FIG. 4A, the changeovercontacts 82 connect the pad 14A to V_(batt) and the pad 14B to groundvia a resistor R1 and to the source of an FET Q1. This forms a circuitin which the source of Q1 is pulled up to V_(batt) via R3, resistor R1being sufficiently large that current drain from V_(batt) and the pulldown effect with respect to R3 is minimised. V_(batt) is also be appliedto the gate of Q1 and to a resistor R2 pulling up the drain of Q1.Resistor R2 is sufficiently large that current drain from V_(batt) isminimised. This state is maintained as long as the pads 14 remainattached to the release liner 15.

To turn the defibrillator on, either or both pads 14 are removed fromthe release liner 15. This breaks the circuit formed by R3 which pulledthe source of Q1 to V_(batt), so that the source of Q1 is now pulled toground via R1. This turns on Q1 and in doing so pulls down the voltageat the drain of Q1 to a value determined by the divider created by R2and R1. This voltage drop 84 is detected by the defibrillator controlcircuitry (not shown) which responds by switching over the contacts 82to connect the pads 14A and 14B to respective high voltage terminals HV1and HV2 within the defibrillator.

The embodiments of FIGS. 3 and 4 assume that the connector 22 is, inuse, already plugged into the defibrillator 12, so the battery power isonly required to be applied when the pads are actually deployed for use.This contrasts with the embodiment of FIG. 1 where it is assumed thatthe connector 22 is not pre-connected to the defibrillator 12, so thatthe mere act of plugging it in can apply power and turn thedefibrillator on.

In the embodiment of FIG. 5 the batteries are not housed in theconnector 22 but instead a flat battery pack 42 is mounted on the rearof one or both pads 14. This requires extra wires 44 to the connector 22to carry the power. As shown in FIG. 6, and similar to the embodiment ofFIG. 3, the power supply circuit may include a spring contact 39 biasedagainst a counter contact 46 but normally held electrically disconnectedtherefrom by an insulating tab 40. The tab 40 is fixed to a releaseliner 48 such that, when the liner 48 is on the pad 14, the tab 40 isinterposed between the contacts 39 and 46. However, when the liner 48 isremoved from the pad 14 the tab 40 is withdrawn from between thecontacts 39 and 46 to complete the power circuit and power up thedefibrillator 12 for use.

In the embodiment of FIG. 7, when the pads 14 are not in use they arestowed (attached, for example, by Velcro) in a shallow depression orrecess 50 in the defibrillator 12 housing and the connectors 22 and 28are pre-engaged (in FIG. 7 the two connectors are shown as a single item22/28 for simplicity). In this case the batteries 24 are housed in theconnector 22, as in FIG. 1. Within the defibrillator 12 the power supplycircuit includes a pair of contacts 52 and 54 which are biased towardsone another but normally held apart by an insulating pin 56 which isremovably inserted into the defibrillator housing from outside. This pin56 also cooperates with the pad leads 18 (or with the pads 14themselves) such that when the pads 14 are removed from the recess 50the pin 56 is automatically removed from between the contacts 52, 54 sothat power from the batteries 24 is automatically connected to thedefibrillator 12.

The embodiment of FIG. 8 is similar to that of FIG. 7 except that thebatteries 24 are again no longer housed in the connector 22 but come inthe form of a flat battery pack 58 housed, together with the pads 14, ina tray 60 which fits in the recess 50. In this case either the act ofremoving the pads from the tray, or the act of removing the tray,removes the pin 56 from between the power contacts 52, 54.

FIG. 9 shows a variation of FIG. 7 wherein one of the pads 14 is fixedto the rear of the defibrillator 12 housing and its electricalconnection to the defibrillator is either made directly through thedefibrillator housing via a contact 62 in the housing wall or via a lead18 and the connectors 22/28 as in FIG. 7 (where the connection to thepad 14 is made directly via the contact 62 there will only need to beone terminal 20 on the connector 22 and correspondingly only oneterminal 30 on the connector 28). In this embodiment the operation issimilar to that of FIG. 7 except that the defibrillator 12 itself isplaced on the patient's chest and effectively becomes one of the patientpads. The other pad 14 performs the device turn-on operation as bypulling out the mechanical block (pin 56) in the power supply circuitwhen it is pulled away from the defibrillator 12.

FIG. 10 is an exploded perspective view of a practical implementation ofthe embodiment of FIG. 7 (the leads 18 are not shown). The defibrillator12 comprises upper and lower housing halves 12 a and 12 b which containa digital printed circuit board (PCB) 70 and a high voltage PCB 72. Thebatteries 24 are accommodated in the connector 22 which plugs into thesocket connector 28 in the upper housing half 12 a. The recess 50 isformed in the lower housing half 12 b and contains the pads 14 when theyare not in use. The insulating member 56 enters a slot 74 in the lowerhousing half 12 b to be interposed between the contacts 52 and 54 (FIG.7) and is operatively coupled to the pads 14 and/or their leads so thatit is withdrawn from the slot 74 when the pads are removed from therecess 50.

Referring now to FIGS. 11 to 17, a further embodiment of the inventioncomprises a defibrillator 12 having a recess 100 (FIG. 15) to slidablyreceive a housing 102 which accommodates both the batteries 24 and thepads 14 in common and also functions as the connector 22.

The housing 102 comprises an upper shallow tray-like recess 103A foraccommodating the pads 14 (as shown in FIGS. 13 and 17) and a deeperrecess 103B occupying part of the area of the tray-like recess 103A foraccommodating the batteries 24. Accordingly, the housing 102 has astepped lower surface 104, FIG. 14, with a riser portion 104A joiningthe two portions 104B and 104C of the lower surface which correspondrespectively to the tray-like and battery recesses 103A, 103Brespectively and which are accordingly at different levels.

On the inside of the housing 102 the riser portion 104A has pairs ofhigh voltage input and power output terminals 20, 26 respectively (FIG.11), the pads 14 being connected to respective ones of the terminals 20by respective leads 18 and the batteries 24 being connected in seriesacross the terminals 26. The leads 18 pass under a strain relief member106 to prevent strain on the connection between the leads 18 andterminals 20. The terminals 20, 26 pass fully through the wall of thehousing 102 at the riser portion 104A to appear exposed at the lowersurface 104, FIG. 14.

The recess 100 in the defibrillator 12, FIG. 15, has a stepped formationcomplementary to that of the housing 102, the recess 100 extending tothe edge 108 of the defibrillator 12. The recess 100 has a riser portion100A having pairs of terminals 30, 32 for mating with the correspondingpairs of terminals 20, 26 on the housing 102, the terminals 30,32extending through the wall of the defibrillator housing at the riserportion 100A and being connected to the internal circuitry (not shown)of the defibrillator 12.

In use, the batteries 24 are inserted in the recess 103B of the housing102 and then the pads 14 are laid in the shallow recess 103A over thebatteries, FIG. 13. The leads 18 are neatly coiled up above thebatteries 24. The pads are joined by a frangible link 41 (FIG. 16) aspreviously described, this being connected by a short piece of cord 43to the strain relief member 106 (or elsewhere to the housing 102). Thepads 14 are covered with a peel-off protective cover (not shown).

Now the housing 102 is slid into the recess 100 from the edge 108 of thedefibrillator 12, the housing 102 being slid in a directionsubstantially parallel to the plane of the shallow recess 103A. Thesliding movement is guided by ribs 110 on opposite sides of the housing102 engaging under corresponding ribs 112 on opposite sides of therecess 100. When the housing 102 is fully home in the recess 100resilient ears 114 on opposite sides of the housing 102 engage slots 116on opposite sides of the recess 100, thereby retaining the housing 102in position in the recess 100. In the fully home position the terminals20, 26 exposed on the underside of the housing 102 (FIG. 14) mate withthe terminals 30, 32 respectively on the defibrillator 12.

To use the defibrillator, the covering over the pads 14 is peeled offand the pads 14 removed from the recess 103A. This act of removal seversthe frangible link 41 thus powering up the defibrillator 12 aspreviously described (alternatively the cord 43 may be omitted and thelink 41 severed by separation of the pads 14). This is the situationshown in FIG. 11, where the pads 14 are shown deployed for use. Afteruse, the housing 102 is removed from the defibrillator 12 by squeezingthe ears 114 towards one another to disengage from the slots 116 andsliding the housing 102 out of the recess 100. Now a fresh housing 102containing pads and batteries ready for the next use of thedefibrillator is slid into the recess 100.

FIGS. 18 and 19 are views, similar to FIGS. 13 and 17, of a combined padand battery housing of a still further embodiment of the invention.Since the main defibrillator body 12, as seen for example in FIG. 15,remains substantially unchanged in this embodiment, only the combinedpad and battery housing 102 is shown. As before, the housing 102 is slidinto the recess 100 from the edge 108 of the defibrillator 12 until theresilient ears 114 engage the slots 116 to retain the housing 102 inposition in the recess 100 with the terminals 20, 26 mating with theterminals 30, 32 respectively.

However, in this embodiment the tray-like recess 103A is closed by a lid200 which can be slid off the housing 102 in the direction of the arrowin FIGS. 18 and 19 by pulling on a tab 202 fixed to the front edge ofthe lid. The pads 14 are removably fitted to the underside of the lid200, so that removal of the lid automatically removes the pads 14 fromthe recess 103A. The act of sliding the lid 200 out of the housing 102automatically breaks the frangible link 43 (not shown in FIG. 19) topower up the device as previously described. The lid 200 is releasablyretained in position on the housing 102 by integrally moulded pips 204on the edge of the housing which resiliently engage respective shallowdepressions 206 on the edge of the lid.

The invention is not limited to the embodiments described herein whichmay be modified or varied without departing from the scope of theinvention.

1. A disposable electrode assembly for a portable defibrillator, theassembly comprising at least one defibrillator electrode, at least onebattery for powering the defibrillator, and a connector for connectingthe electrode and battery to the defibrillator, the connector havingpower output terminals for connecting the at least one battery to thedefibrillator and at least one high voltage input terminal for applyinga defibrillation voltage to the at least one electrode.
 2. An assemblyas claimed in claim 1, wherein the assembly comprises two defibrillationelectrodes.
 3. An assembly as claimed in claim 2, wherein thedefibrillation electrodes are electrically connected externally of thedefibrillator by a frangible connection which is broken when theelectrodes are deployed for use.
 4. An assembly as claimed in claim 1 or2, wherein the at least one defibrillation electrode is sealed in apouch and further including means for completing a power supply circuitto the power input terminals upon opening the pouch.
 5. An assembly asclaimed in any preceding claim, wherein the battery is housed in theconnector.
 6. An assembly as claimed in any of claims 1 to 4, whereinthe battery is mounted on the rear of the at least one defibrillationelectrode.
 7. A combination of a defibrillator and an assembly asclaimed in any one of claims 1 to
 6. 8. A combination as claimed inclaim 7 when dependent on claim 1 or 2, wherein the at least onedefibrillation electrode has a stowage location on the defibrillatorhousing and removal of the electrode from the stowage locationautomatically connects power to the defibrillator.
 9. A combination asclaimed in claim 7 when dependent on claim 1, wherein the assemblycomprises one defibrillator electrode and a second defibrillatorelectrode is attached to the exterior of the defibrillator housing. 10.A combination as claimed in claim 7 when dependent on claim 23, whereinthe defibrillator has circuitry to determine when the frangible link isbroken and upon such determination to complete a power supply circuit inthe defibrillator.
 11. A combination as claimed in claim 7 whendependent on claim 2 or as claimed in claim 10, wherein the assemblycomprises a common housing for the defibrillation electrodes and the atleast one battery, the common electrode/battery housing being removablyfitted to the defibrillator housing and having power output and highvoltage input terminals for connection to corresponding terminals on thedefibrillator housing.
 12. A combination as claimed in claim 11, whereinthe common housing is slidable into a complementary recess in thedefibrillator housing, the sliding movement bringing the terminals onthe two housings into engagement.
 13. A combination claimed in claim 12,wherein the common housing comprises a shallow upper tray-like recessfor accommodating the defibrillator electrodes and a deeperbattery-containing recess occupying part of the area of the tray-likerecess whereby the common housing has a stepped lower surface, whereinthe defibrillator housing has a stepped recess complementary to that ofthe lower surface of the common housing, wherein the common housing isslid into the recess in the defibrillator housing from an edge thereofin a direction substantially parallel to the plane of the tray-likerecess, and wherein the engaging terminals are located on riser portionsof the lower surface of the common housing and the complementary recessin the defibrillator housing.